Anyone have a vid, youtube or other for Valve spring or Cam replacement How To or

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turbo96max

Member
Joined
Jun 6, 2007
Im having an issue which friendly local member support points to weak Valves springs. I need to throw in some springs to test out our theory and I am wondering if there are any known youtube links on this how to. Or maybe another member has recorded the job themselves and has the ability to upload the vid.


issue backgound info:

car runs stronger part throttle at 17 psi VS wot at higher boost.
feels kinda like 'rev limiter" "soft flutter" , boost also fluctuates alot +- 3,4 lbs on the gauge, and have experienced high back pressure on turbine / hot side. Log show rpms in 3rd floating from 5000-5200 back down to 5000 then up..engine doesnt want to rev much past 5200-5300 it seems.
 
Same type of symptom can be coilpack related in my case. Revlimiter type of flutter sticking in the 4 k range but stay in it and it gets past it. Coil pack ohmed high and new one cured it but now i burnt this one out too damn it
 
If anyone just "throws" a set of springs on their engine like they did in that video without measuring the springs pressures and installing at the correct heights they may go backwards. Those 980 springs are probably about 70-75lbs on the seat the way they installed them. Less if valve jobs have been done and the valves are sunk.


BPE2013@hotmail.com
 
Bison, enlighten the crowd then because I am curious. What do you mean installing at the correct heights?
 
Bison, i plan on using the lt1 springs just to test and assure it cures the issue . And then order a complete cam kit . From research those lt1s are ovet 100# . Granted im not going to measure height. Do you recommend shimming the a bit to make sure its on the tighter side? I plan on using rotella w a lucas zddp engine containing lubricant additive .

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baby6 said:
Bison, enlighten the crowd then because I am curious. What do you mean installing at the correct heights?
Click to expand...
Springs pressures vary at different heights (or they wouldn't be a spring).
More compression means more pressure. The increase in pressure over a given distance is the rate. Knowing what the pressure is at a given height is very important. If you just throw on a set of 980 springs with no shims or anything to get the installed height around 1.800" you aren't helping a situation where spring pressure was inadequate. The difference between 1.700 and 1.77 could be 15-20lbs on even a low rate spring like a 980. With a high rate spring the difference would be even more. The spring has to be able to control the valvetrain and avoid coil bind. Usually springs are "happier" when they are run .060-.080" from coil bind. They last longer and stabilize the valvetrain better. So you figure out what seat pressure you want, what rate, and what your maximum compression (actual valve lift) will be and it's all simple math to determine which spring would be a good selection. I prefer to go backward from coil bind and see how much room I have then select a spring that will hit the seat pressures I want after adding the lift back in. Bottom line is the springs need to be measured in a spring tester and checked. If you're shooting for 90lbs on the seat you may find you need to install around 1.680-1.700. You would use the appropriate measuring device and shim the springs and or use different valve locks to achieve the heights you want. This is the preferred procedure for replacing spring with the heads on the car. If a builder was blue printing they may equalize all the valve depts in the head first then cut the spring seats to achieve the pressure they want with minimal shimming.


BPE2013@hotmail.com
 
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